Answer:
31
Step-by-step explanation:
To rationalise 7 + 3[tex]\sqrt{2}[/tex] , multiply by its conjugate
The conjugate of 7 + 3[tex]\sqrt{2}[/tex] is 7 - 3[tex]\sqrt{2}[/tex] , then
(7 + 3[tex]\sqrt{2}[/tex])(7 - 3[tex]\sqrt{2}[/tex]) ← expand using FOIL
= 49 - 21[tex]\sqrt{2}[/tex] - 21[tex]\sqrt{2}[/tex] - (3[tex]\sqrt{2}[/tex])²
= 49 - 18
= 31
